1. Technical Field
The present invention relates to a method and apparatus for controlling, reducing or eliminating infestations of mollusks.
2. Description of Related Art
Mollusks cause both economic harm as well as harm to human health. In terms of economic harm, mollusks such as zebra mussels (Dreissena polymorpha), quagga mussels (Dreissena rostriformis bugensis) and Asian clams (Corbicula fluminea) infest waterways, clog water intake pipes from water supplies, including industrial water sources. In particular, the zebra mussel, Dreissena polymorpha, attaches to and clusters atop virtually any solid surface. This causes blockage or severely restricted water flow when the surface is a water intake pipe as the mussels clog the flow path in the pipe. In addition, the mussels attach to ships' ballasts.
Several mollusk species are also carriers (“vectors”) of debilitating diseases, such as schistosomiasis caused by flat worms of the Schistosoma type, fascioliasis caused by flat worm of the Fasciola, Clonorchis, and Opisthorchis type, paragonimiasis caused by the flatworm of the Paragonimus type. Some 350 snail species, especially in the genera Biomphalaria, Bulinus, Oncomelania, Tricula, and Lymnaea, are estimated to be of possible medical or veterinary importance as intermediate hosts of human parasites. Often, the disease-carrying capabilities are manifested in parts of the world that are relatively impoverished, and where public health care resources are constrained. Thus, the mollusks cause human misery over large populations, particularly in Africa and Asia.
In addition, species of mollusk attack and devour or damage vital crops. For example, the Golden Apple snails (Pomacea canaliculata) and the Australian rice snails (Isidorella new combi) are serious rice and taro crop destroying pests, respectively, in parts of South East Asia where rice is a staple food, and in Australia. The snails have the capability to hibernate underground or in protected areas and emerge when crop planting commences and the rice paddy fields are watered. (The term “aestivation” is used to describe this underground hibernation of snails. For simplicity the word hibernation will be used herein.) The snails graze on the tender young rice or taro shoots causing large crop losses. In addition, to the extent that the snails may be carriers of a disease, the laborers that work the paddy fields may become infected.
Mollusks are ubiquitous and may be found in almost any aquatic-type environment, including running water (e.g. rivers, creeks and streams), lakes and dams, industrial water treatment basins, and, as mentioned above, rice paddy fields. They multiply rapidly, have few predators, and cause economic harm as well as harm to human health.